Chapter 3 COMD notes

Anatomy and Physiology

• Anatomy: Refers to the structures of the body, such as the eyes and ears.

• Physiology: Refers to the functions of these structures, e.g., sight for eyes and audition for ears.

Nervous Systems

• There are two major nervous systems:

  1. Central Nervous System (CNS):

     • Comprises the brain and spinal cord.

  2. Peripheral Nervous System (PNS):

     • Consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves.

Functions of the Nervous System

• Sensory Information:

  • Carries sensory information from the body to the brain.

• Motor Information:

  • Transmits motor information from the brain to the body.

• CNS Damage:

  • Damage to the CNS can result in various physical problems, based on location and severity.

Protective Structures

• Bones:

  • Cranium and vertebral column serve as the first line of defense.

• Meninges:

  • Composed of three layers:

    • 1st layer: Pia Mater

    • 2nd layer: Arachnoid Mater

    • 3rd layer: Dura Mater

• Cerebrospinal Fluid (CSF):

  • Circulates between the pia and arachnoid maters.

Brain Overview

• Control Center:

  • Initiates and regulates almost all sensory, motor, and cognitive functions.

• Parts of the Brain:

  • Brainstem

  • Cerebellum

  • Cerebrum

• Location:

  • Located atop the spinal cord, it acts as a relay station between body and brain, managing important functions like cardio and respiratory activities.

Cerebellum Functionality

• Muscle Coordination:

  • Maintains muscle tone and monitors movement range/strength.

• Body Positioning:

  • Maintains posture and equilibrium.

• Limited Cognitive Role:

  • Involved primarily in physical coordination rather than high-level cognitive tasks.

Cerebral Functions

• Cognitive Function:

  • Involves thinking, rationalization, and problem solving.

• Hemispheres:

  • The brain has two mirror image hemispheres (left and right) separated by the longitudinal fissure, connected by the corpus callosum for communication.

    • Contralaterality: Left hemisphere controls the right side of the body and vice versa due to the crossing of nerve pathways (decussation).

Lobes of the Brain

• Frontal Lobe:

  • Responsible for personality, executive functions, and Broca’s area (speech production).

• Parietal Lobes:

  • Involved in comprehending oral/written language and sensory integration.

• Temporal Lobes:

  • Heschl's gyrus interprets auditory input (left side) and Wernicke’s area is responsible for language comprehension (left side).

• Occipital Lobe:

  • Processes visual information, and damage can lead to cortical blindness.

Nervous Connections

• Spinal Nerves:

  • 31 pairs that extend from the spinal cord to the body's periphery.

• Cranial Nerves:

  • 12 pairs important for sensory functions, particularly for speech, language, hearing, and swallowing.

  • Cranial Nerve Functions:

    • I Olfactory: Smell

    • II Optic: Vision

    • III Oculomotor: Eye movements (motor)

    • IV Trochlear: Eye movement

    • VI Abducens: Eye movement

Communication-Related Cranial Nerves

• VII Facial:

  • Taste sensation, facial movements.

• VIII Acoustic:

  • Hearing and balance.

• IX Glossopharyngeal:

  • Tongue sensation and palatal movement, pharyngeal movement.

• X Vagus:

  • Taste sensation, palatal and pharyngeal movement, laryngeal movement.

• XI Accessory:

  • Head/shoulder movements.

• XII Hypoglossal:

  • Tongue movements.

Respiratory System

• Respiration:

  • Involves breathing (drawing oxygen into lungs, releasing carbon dioxide).

• Upper Respiratory System:

  • Includes trachea, larynx, oral, and nasal cavities.

• Lower Respiratory System:

  • Encompasses lungs, bronchi, and alveoli.

• Control:

  • Regulated by the brainstem; typically involuntary but can be voluntary.

Phonatory System

• Function:

  • Converts air from respiration into sound.

• Pharynx:

  • Tube from nasal cavity to esophagus; consists of three sections: naso, oro, and laryngo-pharynx.

• Larynx:

  • Cartilaginous structure located atop the trachea, pivotal in sound production.

Vocal Folds

• Composition:

  • Thin tissue sheets that vibrate to create sound.

• Endoscopy:

  • Used to examine phonation.

Articulatory System

• Phoneme production:

  • Involves changing sounds through articulation utilizing various articulators (e.g., maxilla, mandible, tongue).

• Speech Sounds:

  • Approximately 40-45 sounds in Standard American English (SAE).

Anatomy of Hearing

• Complex Organ:

  • Consists of the outer ear, middle ear, and inner ear.

• Outer Ear:

  • Comprises the pinna, external auditory canal, and tympanic membrane.

• Middle Ear:

  • Contains three ossicles (malleus, incus, stapes) which convert sound waves to mechanical energy.

Hearing Screening

• Components:

  1. Visual Inspection:

     • Checking the tympanic membrane.

  2. Tympanometry:

     • Measures middle ear pressure.

  3. Pure Tone Testing:

     • Evaluates hearing thresholds at specific frequencies.

Inner Ear Dynamics

• Structure:

  • Consists of chambers (vestibule, semicircular canals, cochlea) housed in the temporal bone.

• Functionality:

  • Converts mechanical energy to hydraulic energy; the cochlea contains hair cells that connect to the auditory nerve sending signals to the brain.

Swallowing Process

• Phases:

  1. Oral Phase:

     • Involves preparing and transporting the bolus.

  2. Pharyngeal Phase:

     • Protects the airway during swallowing.

  3. Esophageal Phase:

     • Propulsion of food through peristalsis into the stomach.